This is a proposal to support a workshop entitled "Oral Retinoids: Mechanisms and Efficacy in Disorders of Keratinization and Acne". A large group of investigators have been using these agents, but the number of patients treated by each investigator is relatively small. The diseases that have been treated include cystic and conglobate acne, psoriasis, pityriasis rubra pilaris, Darier's disease, lamellar ichthyosis, congenital ichthyosiform erythroderma, and epidermolytic hyperkeratosis. Oral retinoids are also being used experimentally to prevent basal cell epitheliomas. The workshop will enable the interchange between dermatologists and between dermatologists and basic scientists relative to the mechanisms of action, pharmacology, toxicology and clinical use of oral retinoids in dermatological disease.